The present invention relates to industrial process transmitters and sensors. In particular, the invention relates to the configuration of a process transmitter with information specific to an attached sensor peripheral component.
Industrial process transmitters and sensors are used to sense various characteristics of fluids flowing through a conduit or contained within a vessel and transmit information about those process characteristics to a control, monitoring and/or safety system remotely located from the process measurement location. A sensor assembly generally includes a sensor, sensor wires, isolating materials and installation fittings. The sensor assembly senses a process parameter, for example, pressure, temperature, pH or flow rate. A process transmitter electrically connected to the sensor assembly by the sensor wires receives a sensor output signal from the sensor assembly. The transmitter reads the sensor output signal received from the sensor assembly and converts it to information accurately representing the process parameter. Finally, the transmitter sends the information to the control system.
In many applications, the sensor assembly attaches to a peripheral component to protect the sensor assembly or enhance its performance. For example, a temperature sensor assembly may attach to a thermowell. The thermowell is designed to be in physical contact with the fluid to protect a temperature sensor within the temperature sensor assembly from physical damage from the fluid, e.g., impacts, corrosion, etc., while efficiently conducting heat between the fluid and the temperature sensor. A thermowell must be compatible with an attached temperature sensor assembly to provide adequate protection while efficiently conducting heat between the fluid and the temperature sensor. Attaching a temperature sensor assembly to the wrong size or style of thermowell may result in damage to the sensor assembly or poor performance in measuring fluid temperature. In addition, a thermowell may be degraded over time as the surface of the thermowell is worn away by the physical and/or chemical action of the fluid which may result in compromised protection for the temperature sensor assembly. A thermowell may also suffer from the accumulation of material from the fluid on the surface of the thermowell (fouling) resulting in poor temperature measurement performance due to the insulating effects of the accumulated material.
Thus, sensor peripheral components, although generally much simpler than, for example, an attached sensor assembly, have important characteristic information specific to a particular sensor peripheral component. In the case of a thermowell, important characteristic information includes, for example, thermowell type, typically located on a metal tag attached to the thermowell; fouling diagnostics information and wake frequency calculation parameters manually entered into an attached process transmitter; and maintenance schedules for inspection and replacement recorded in a remote database. Metal tags can be lost or obscured. Manually entering information into the process transmitter is a time-consuming process requiring the attachment of a separate electrical connection and, as with any manual process, is prone to error. Remote maintenance schedules may not be readily accessible in the field and may not reflect actual usage information. Process measurement accuracy and reliability depend, in part, on the availability of the characteristic information for an attached sensor peripheral component.